Photographic elements containing polymeric ultraviolet absorbing compounds



' April,14, 1959 DENSITY DENSITY J. A. VAN ALLAN r-rrm. 2,882,150 PHOTOGRAPHIC ELEMENTS CONTAINING POLYMERIC ULTRAVIOLET ABSORBING COMPOUNDS Filed 001:. 22, 1954 FILTER LAYER CONTAINING POLYMER/C ULTRAVIOLET ABSORBER will/111 1 m3:

WAVELENGTH (MIL) 2002 4 6 83002 4 6 84002 WAVELENGTH James A ;VanA llan Jack LRMfilliams INVENTORS BY PM MW ATTORIVE Y6 United States Patent PHOTOGRAPHIC ELEMENTS CONTAINING POLY- ggERIC s ULTRAVIOLET ABSORBING COM- James A. Van Allan and Jack L. R. Williams, Rochester,

N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Application October 22, 1954, Serial No. 464,095

4 Claims. (Cl. 9611) This invention relates to new products and new photographic elements protected against the harmful effects of ultraviolet radiation.

It is known that certain materials such as cellulosic films and photographic layers, are adversely affected by ultraviolet radiation when such materials are exposed .to daylight. In the case of photographic layers, the ultraviolet radiation sometimes causes undesired exposure of the layer, or layers, since photographic silver halide emulsions are sensitive to blue, violet and ultraviolet regions of the spectrum, in addition to any other sensitivity which may be given them, and in the exposure of such material, it is frequently desirable to prevent the action of ultraviolet light on the sensitive emulsion. This is especially true in the case of photographic materials designed for use in color photography where the film has been sensitized to the longer wavelength regions where it is desirable to record only the rays of the visible spectrum.

Color photographs on multilayer photographic material, particularly where the dye images are formed in sensitive emulsion layers by color development, are susceptible to fading and discoloration by the action of ultraviolet radiation to which the photographs are subjected during viewing. It is also known that the residual cou- -plers contained in the emulsion layers after formation of the picture images in certain processes are attacked by ultraviolet radiation and form a stain which is undesirable in the finished photograph. The action of ultraviolet radiation on finished color photographs is particularly noticeable in positive prints on paper or other opaque supports, since this type of print is frequently viewed in daylight where there is a high content of ultraviolet radiation. This dye fading and yellowing appears to be caused primarily by those wavelengths of light which lie close to the visual region of the spectrum, i.e. 260-400 millimicrons.

. vWe have now found that certain new ultraviolet absorbing compounds can be used to overcome the aforementioned ditficulties Without attendant harmful action by the ultraviolet absorbing compounds.

It is, therefore, an object of our invention to provide new compounds and methods of making these new compounds. Another object is to provide photographic elements protected against the harmful effects of ultraviolet radiation. A further object is to provide photographic color materials which have been protected against the harmful effects of ultraviolet radiation. Other objects will become apparent from a consideration of the following description and examples.

. It is known in the art that the incorporation of a substance which selectively absorbs ultraviolet radiation prevents or reduces some of the disadvantages presented through the use of cellulosic films or photographic layers. However, the substances which have been previously incorporated to produce this desirable effect suffer from the disadvantage-that they either (1) tend to, leach or fbleedff from their films, and their effectiveness is thus 2,882,150 Patented Apr. 14, 1950 lost, or (2) tend to separate or crystallize from their :iolid solutions, resulting in a hazy and sometimes brittle These difiiculties are overcome in the instant invention by attaching a macromolecule to compounds which have the property of absorbing the undesirable ultraviolet radiation, but have no substantial absorption in the visible region of the spectrum, i.e., from about 400-700 mu. Such a combination helps to prevent diffusion and at the same time makes orientation of the molecule increasingly difficult, thus reducing the danger of crystallization. Moreover, the customary vehicles employed in the photographic art have a greater compatibility for the polymeric ultraviolet absorbing compounds of our invention than for the nonpolymeric compounds alone.

The polymeric ultraviolet absorbing compounds of our invention are represented by polymerized monoethy lenically-unsaturated compounds having chemically attached thereto a compound having its maximum absorption between 260-400 mu with no substantial absorption between 400-700 mu. The polymeric components useful in practicing our invention have been previously described in the prior art, as have many of the ultraviolet absorbing components. The chemical combination can" be through such steps as acetalization, quaternization, etc. Since the ultraviolet absorbing component is reacted with a polymerized monoethylenically-unsaturated compound containing reactive chemical groups, it is apparent that the reactionneed not be complete in order to obtain the advantages of our invention. That is, not all of the reactive chemical groups in the polymerized compounds need undergo reaction. However, we have found that it is ordinarily advantageous to have at least ten percent of such reactive groups combined with the ultraviolet absorbing component.

Typical of the polymeric absorbing compounds of our invention are compounds represented by the following two general formulas:

"methoxyphenyl, m-, and p-ethoxyphenyl, ,B-hydroxyethylphenyl, 0-, m-, and p-chlorophenyl, 0-, m-, and phydroxyphenyl, o-., m-, and p-sulfophenyl (and alkali metal salts thereof, e.g. sodium, potassium, etc.), 4-methoxy-3-sulfophenyl (and alkali metal salts thereof, e.g. sodium, potassium, etc.), 2,4-dicarboxymethylphenyl (and alkali metal salts thereof, e.g. sodium, potassium, etc.), 0-, m-, and p-carboxyphenyl (and alkali metal salts thereof, e.g. sodium, potassium, etc.), 3-(3-sulfobenzamido)phenyl (and alkali metal salts thereof, e.g. sodium, potassium, etc.), o-carbobutoxyphenyl, diamylphenoxyaeetoxyphenyl, etc. (e.g. a carbocyclic aromatic group of the benzene series containing from 6 to 24, and more particularly 6 to 11, carbon atoms), :2 represents apositive integer of from 1 to 2, and X represents a halogen atom, such as chlorine, bromine, etc.

The polymeric absorbing compounds represented by Formula I above can advantageously be prepared by condensing polyvinyl alcohol together with a compound represented by the following general formula:

wherein R and R have thevalues defined above and R represents alower alkyl group, such as methyl, ethyl, etc. The condensations can be effected in the presence of an inert diluent, such as 1,4-dioxane, benzene, etc. An acidic condensing agent, such as hydrochloric acid, phosphoric acid, etc. can be employed, if desired. Heating accelerates the condensations, although temperatures no higher than room temperature can advantageously be employed. As noted above, all of the hydroxyl groups o'fth'e polyvinyl alcohol need not be acetalized, although the higher the acetalization the more effective is the resulting polymeric compound as an ultraviolet absorbing substance. Ordinarily, the polymeric product resulting from the condensation contains groups formulated above as Formula I and also some unreacted polyvinyl alcohol units. The intermediates represented by Formula III above can advantageously be prepared by condensing together an ester of chloroacetic acid, e.g. ethylchloroacetate, with a compound represented by the following general formula:

wherein R and R have the values given above, followed by the condensation of the resulting product with an aromatic aldehyde (see Sawdey and Van Allan U.S. application Serial No. 457,304, filed September 20, 1954, now U.S. Patent 2,784,087, issued March 5, 1957). The condensations of the compounds of Formula IV with the alkylchloroacetates can advantageously be effected in the presence of an acid-bonding agent, e.g. pyridine. The intermediates represented by Formula IV above can be prepared as described by Wohl et al., Berichte, volume 22, page 569. The method of Wohl et al. comprises reacting an aminoacetal with an arylisothiocyanate (R--NCS), e.g. phenylisothiocyanate. The structures represented by Formula II above can advantageously be prepared by reacting together a compound selected from those represented by the following general formula:

CHI-X wherein X has the values given above, and a compound represented by the following general formula:

(VI) CHr-CH:

wherein R has the values given above. The reaction can be effected by simply heating the mixture of compounds together at a temperature of from about 40 C. to the reflux temperature of the mixture. An inert diluent, such as 1,4-dioxane, benzene, etc. can advantageously be employed.

The structures represented by Formula V above can be prepared as described in U.S. Patents 2,631,999; 2,632,- 000; and 2,632,001, issued March 17, 1953.

The intermediates represented by Formula VI above can advantageously be prepared by heating together an ester of chloroacetic acid, e.g. ethylchloroacetate, and a compound selected from those represented by the following general formula:

(VII) CH2 wherein n has the value given above, the reaction being advantageously carried out in the presence of an aldehyde represented by the following general formula:

(VIII) R1- 0:0

wherein R has the values represented above. Alternatively, the compound of Formula VII can be reacted With the alkylchloroacetate and the product of this reaction then reacted further with the aldehyde represented by Formula VIII.

Figure 1 of the accompanying drawing illustrates schematically a cross-sectional view of a sensitive photographic element having an ultraviolet filter layer containing one of the compounds represented by the above general Formula II. These ultraviolet absorbing compounds can be incorporated in the photographic element in a variety of ways, depending on the ultimate use of the photographic element and the degree of protection desired. Advantageously, the ultraviolet absorbing compound can be dissolved or dispersed in a solvent medium together with a colloidal binder, such as gelatin, cellulose esters (e.g. cellulose acetate, etc.), synthetic resins (e.g. poylvinyl acetals, hydrolyzed polyvinyl acetate, etc.), etc and the resulting mixture coated over the light-sensitive layer of the photographic element. Where the photographic element is a material intended for use in color photography, the ultraviolet filter layer need not be an outer layer, but this layer can be placed over one of the layers subject to the harmful effects of ultraviolet radiation. For example, in a multilayer material com prising three differentially sensitized layers, the red sensitive layer being adjacent to the support, the green sensitive layer being superposed on the red sensitive layer, and the blue sensitive layer being outermost with respect to the other light-sensitive layers, the ultraviolet filter layer can be placed between the blue and green sensitive layers. Alternatively, the ultraviolet filter layer can be placed between the green and the red sensitive layers. If desired, the material useful in absorbing the-ultraviolet radiation can be incorporated directly in the lightsensitive emulsion instead of, or in addition to, being present in another layer. The amount of ultravioletabsorbing compound used can be varied, depending upon leaguefie effect desired and the use to which the material is to The water-soluble compounds of Formulas I and II above (e.g. those containing alkali metal salts of carboxyphenyl, sulfophenyl, etc. groups) can be incorporated into the photographic element by simply bathing the element in an aqueous solution containing the ultraviolet absorbing compound. Where the outer layer contains gelatin, the ultraviolet absorbing compound becomes adsorbed to this layer. The ultraviolet absorbing compounds can be incorporated into the photographic element before or after (i.e. during processing) exposure. The support of the photographic element can be transparent, such as a cellulose ester (e.g. cellulose acetate, etc.) support, or the support can be opaque, such as a paper support. Other supports, such as glass, metal, etc. can be employed, if desired.

' The following examples will serve to illustrate the manner whereby we prepare the compounds of Formulas I and II above.

Example I.-Plymeric acetal To a solution of 10 g. (0.25 mol.) of polyvinyl alcohol in 100 ml. of water there was added a solution of 1 g. (0.002 mol.) of 3-(fi,B-diethoxyethyl)-2-phenylimino-5- (o-sulfobenzal)thiazoline (prepared by heating (AB-diethoxyethyl)-3-phenylthiourea together with ethylchloroacetate and pyridine) in 50 ml. of 1,4-dioxane. Following the addition of 5 ml. of concentrated hydrochloric acid, the reaction mixture was stirred for 16 hours at room temperature. The desired polymer was precipitated in ethanol and reprecipitated from water into ethanol to yield 4.5 g. of dry polymer. A 1 g. sample of the polymer was dissolved in 100 ml. of water and the absorption of this solution measured in the usual mannet. The curve obtained is shown in Fig. 2 of the drawing and is represented by line A. The aqueous sample was diluted to 400 ml. with water and the absorption of this dilute solution measured. The absorption curve of this dilute solution is represented by curved B in Fig. 2. These curves show that a significant quantity of the ultraviolet absorbing component was present in the polymer.

Example II.-P0lymeric quaternary salt To a solution of 24 g. (0.088 mol.) of 2-(o-methoxybenzal) 3 keto 2,3,3a,4,5,6 hexahydro 321,7- diazabenzothiophene in 150 ml. of 1,4-dioxane there was added a solution of 17.3 g. (0.1 mol.) of poly-p-bromomethylstyrene in 150 ml. of 1,4-dioxane. The resulting solution was heated at 60-65 C. for 3.5 hours, and the precipitated quaternary salt filtered. The quaternary salt was dissolved in a mixture of 150 ml. of chloroform with 50 ml. of methanol and finally precipitated again in 1,4- dioxane. A 1 g. sample was dissolved in 100 ml. of 1:2 methanol-chloroform and the absorption of the solution measured in the usual manner. The absorption curve for this solution is given as curve C in Fig. 3. The solution was diluted to one-tenth of its original concentration and the absorption of the dilute solution measured. This is given as curve D of Fig. 3. The solutions showed a maximum absorption at 378 mu and a log extinction coefiicient of 3.919.

Analysis.-Calculated for: C H O N SBR: C, 58.5; H, 5.1; N, 5.9. Found: C, 56.9; H, 4.8; N, 3.6.

The diazabenzothiophene compound used in the above example was prepared as follows: 60 g. of 2-mercapto- 3,4,5,6-tetrahydropyrimidine (prepared in 85% yield from trimethylenediamine and carbon disulfide) and 100 ml. of ethylchloroacetate were heated to 140-145 C. for four hours. After cooling, the reaction mixture, which had set to a solid crystal mass, was filtered, washed with benzene and dried. The resulting dry product was dissolved in methanol, and enough piperidine was added to make the reaction mixture basic. o-Methoxybenzaldehyde was then added and the mixture heated under reflux for four hours. The resulting product had a melting point of 132-133" C. and it was pale yellow in color.

The poly-p-bromomethylstyrene used in the above example was obtained by reacting together poly-p-methylstyrene and bromine in a solution of carbon tetrachloride. The polymer was precipitated from the carbon tetrachloride solution by the addition of methanol. Instead of using bromine (liquid) for the bromination, it is possible to use N-bromosuccinimide. Another method of preparing halogenomethylpoly-p-styrenes is decsribed by G. D. Jones in Industrial and Engineering Chemistry, volume 44, pages 2686-2693.

The following example describes the preparation of a photographic coating from one of the new polymeric ultraviolet absorbing compounds of our invention.

Example III 0.5 g. of the polymeric quaternary salt obtained in Example II above was dissolved in 5 ml. of warm dimethylformamide, and 5 ml. of water were immediately added to give a clear yellow solution. This was then added with stirring to 10 ml. of a 10% commercial polyvinyl alcohol solution. This solution was then coated on a glass plate and allowed to dry. On drying, a clear, pale yellow film was formed, which was stripped from the plate. The resulting film was completely opaque to ultraviolet radiation up to 410 mu. Prolonged exposure of the film in an east window caused no visible deterioration and the film provided excellent protection when placed over a multilayer photographic element, which had been exposed and developed to a visible image. Similar results can be obtained by replacing the polyvinyl alcohol solution of Example III with aqueous gelatin solutions.

In a manner similar to that illustrated in Example III above, photographic elements containing a photographic silver halide emulsion layer can be treated with other polymeric ultraviolet absorbing compounds embraced by Formulas I and II above. In those cases where the ultraviolet absorbing compound is not water-soluble, it can be incorporated in the gelatin, or polyvinyl alcohol, solution with the aid of an insert solvent, e.g. ethanol, and be uniformly dispersed throughout the solution before coating.

In the accompanying drawings, Fig. 1 illustrates schematically a cross-sectional view of a photographic element containing a layer having incorporated therein the polymeric quaternary salt obtained in Example II above. As shown in Fig. l, a support 10 of any suitable material, such as cellulose acetate, or paper, having thereon an emulsion layer 11 is coated with a filter layer 12 having incorporated therein the polymeric quaternary salt obtained in Example II. It will be understood that Fig. 1 of the drawing is merely representative of other structures which can be employed in our invention, and that the element can have other layers, not shown, as additional light-sensitive layers, subbing layers, antihalation layers, etc.

By replacing the Z-mercapto-3,4,5,6-tetrahydropyrimidine used in Example II by a molecularly equivalent amount of N,N'-ethylenethiourea, the intermediate represented by Formula VII above wherein n is one can be prepared. Aromatic aldehydes useful in condensing with the reaction product of a compound represented by Formula IV and an ester of chloroacetic acid, as mentioned above, comprise aromatic aldehydes represented by Formula VHI above. The intermediates represented by Formula VI above can also be used as antifoggants in photographic silver halide emulsions.

What we claim as our invention and desire secured by Letters Patent of the United States is:

1. A photographic element comprising a support, at least one photographic gelatino-silver-halide emulsion layer, and incorporated in one of the layers of said photographic element a polymeric acetal compound havwherein R represents a member selected from the group consisting of an aryl group and an aralkyl group, R represents an alkyl group containing from 1 to 2 carbon atoms and R represents an aryl group, at least ten percent of the hydroxyl groups of said polyvinyl alcohol having been condensed with said thiazoline compound.

2. A photographic element comprising a support, at least one photographic gelatino-silver-halide emulsion layer superposed on said support, and an outer gelatin layer containing a polymeric acetal compound obtained by condensing polyvinyl alcohol with a thiazoline compound selected from those represented by the following general formula:

wherein R represents a member selected from the group consisting of a mononuclear aromatic group of the benzene series containing from 6 t 11 carbon atoms and a mononuclear aralkyl group containing from 7 to 8 carbon atoms, R represents an alkyl group containing from 1 to 2 carbon atoms and R represents a carbocyclic aromatic group of the benzene series containing from 6 to 24 carbon atoms, at least ten percent of the hydroxyl groups of said polyvinyl alcohol having been condensed with said thiazoline compound.

3. A finished photographic element comprising a support having thereon a plurality of developed and fixed photographic emulsion layers containing coupled-dye images, at least one of said dye images being subject to fading by the action of ultra-violet radiation, said emulsion layer containing a coupled-dye image subject to fading lying between said support and a gelatin layer containing a polymeric, acetal, ultra-violet absorbing com pound obtained by condensing polyvinyl alcohol with a thiazoline compound selected from those represented by the following general formula:

wherein R represents a member selected from the group consisting of a mononuclear aromatic group of the ben z ene series containing from 6 to 11 carbon atoms and a mononuclear aralkyl group containing from 7 to 8 carbon atoms, R represents an alkyl group containing from 1 to 2 carbon atoms and R represents a carbocyclic aromatic group of the benzene series containing from 6 to 24 carbon atoms, at least ten percent of the hydroxyl groups of said polyvinyl alcohol having been condensed with said thiazoline compound.

4. A photographic element comprising a support, aphotographic gelatino-silver halide emulsion layer, and a gelatin layer containing a polymeric compound obtained by the condensation of polyvinyl alcohol with 3-(fi',fi;- diethoxyethyl) 2 phenylimino 5 -(o sulfobenzal) thiazoline, at least ten percent of the hydroxyl groups of' said polyvinyl alcohol having been condensed with said thiazoline compound.

References Cited in the file of this patent UNITED STATES PATENTS 2,310,943 Dorough et a1. Feb. 16, 1943 2,469,288 Adelson et a1. May 3, 1949 2,562,528 Corner July 31, 1951 2,675,316 Carroll et a1. Apr. 13, 1954 2,677,612 Gaspar et *al. May 4, 1954 2,739,888 Sawdey Mar. 27, 1956 2,739,971 Sawdey et al Mar. 27, 1956 2,753,264 Mochel et a1. July 3, 1956 

3. A FINISHED PHOTOGRAPHIC ELEMENT COMPRISING A SUPPORT HAVING THEREON A PLURALITY OF DEVERLOPED AND FIXED PHOTOGRAPHIC EMULSION LAYERS CONTAINING COUPLE-DYE IMAGES, AT LEAST ONE OF SAID DYE IMAGES, BEING SUBJECT TO FADING BY THE ACTION OF ULTRA-VIOLET RADIATION, SAID EMULSION LAYER CONTAINING A COUPLED-DYE IMAGE SUBJECT TO FADING LYING BETWEEN SAID SUPPORT AND A GELATIN LAYER CONTAINING A POLYMERIC, ACETAL, ULTRA-VIOLET ABSORBING COMPOUND OBTAINED BY CONDENSING POLUVINYL ALCOHOL WITH A THIAZOLINE COMPOUND SELECTED FROM THOSE REPRESENTED BY THE FOLLOWING GENERAL FORMULA: WHEREIN R REPRESENTS A MEMBER SELECTED FROM THE GROUP CONSISTING OF A MONONUCLEAR AROMATIC GROUP OF THE BENZENE SERIES CONTAINING FRIN 6 TO 11 CARBON ATOMS AND A MONONUCLEAR ARALKYL GROUP CONTAINING FROM 7 TO 8 CARBON ATOMS, R'' REPRESENTS AN ALKYL GROUP CONTAINING FROM 1 TO 2 CARBON ATOMS AND R1 REPRESENTS A CARBOCYHCLIC AROMATIC GROUP OF THE BENZENE SERIES CONTAINING FROM 6 TO 24 CARBON ATOMS, AT LEAST TEN PERCENT TO THE HYDROXYL GROUPS OF SAID POLYVINYL ALCOHOL HAVING BEEB CONDENSED WITH SAID THIAZOLINE COMPOUND. 